From: Linus Torvalds <torvalds@woody.linux-foundation.org>
Date: Sun, 9 Dec 2007 18:14:36 +0000 (-0800)
Subject: Avoid double memclear() in SLOB/SLUB
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7fd272550bd43cc1d7289ef0ab2fa50de137e767;p=linux-beck.git

Avoid double memclear() in SLOB/SLUB

Both slob and slub react to __GFP_ZERO by clearing the allocation, which
means that passing the GFP_ZERO bit down to the page allocator is just
wasteful and pointless.

Acked-by: Matt Mackall <mpm@selenic.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/slob.c b/mm/slob.c
index ee2ef8af0d43..773a7aa80ab5 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -330,7 +330,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 
 	/* Not enough space: must allocate a new page */
 	if (!b) {
-		b = slob_new_page(gfp, 0, node);
+		b = slob_new_page(gfp & ~__GFP_ZERO, 0, node);
 		if (!b)
 			return 0;
 		sp = (struct slob_page *)virt_to_page(b);
diff --git a/mm/slub.c b/mm/slub.c
index b9f37cb0f2e6..9c1d9f3b364f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1468,6 +1468,9 @@ static void *__slab_alloc(struct kmem_cache *s,
 	void **object;
 	struct page *new;
 
+	/* We handle __GFP_ZERO in the caller */
+	gfpflags &= ~__GFP_ZERO;
+
 	if (!c->page)
 		goto new_slab;